Converting NumPy array into Python array_like structure?

Question

How do I convert a NumPy array to a Python array_like structure (for example [[1,2,3],[4,5,6]] ), and do it reasonably fast?

Answer 1

Use tolist():

import numpy as np
>>> np.array([[1,2,3],[4,5,6]]).tolist()
[[1, 2, 3], [4, 5, 6]]

Answer 2

NumPy arrays have a tolist method:

In [1]: arr=np.array([[1,2,3],[4,5,6]])

In [2]: arr.tolist()
Out[2]: [[1, 2, 3], [4, 5, 6]]